Thermoplastic structural system and components therefor and method of making same

ABSTRACT

The invention is for a thermoplastic structural system, structural components therefor, and method of producing same in which the structural components are extruded from a thermoplastic material containing a reinforcing constituent flowable through an extrusion die, the structural components being configured for interlocking interconnection.

FIELD OF INVENTION

The present invention relates to the provision of novel structuralsystem and structural components therefor, their method of manufacture,and structures formed therefrom. More particularly, the inventionrelates to the provision of novel interlocking thermoplastic structuralcomponents which can be mass produced at low cost and which can bequickly and easily interlocked together to erect a wide range ofstructures which will require minimal maintenance and will be safe fromtermites, corrosion, rust or rot and will be highly resistant to theeffects of weathering.

Further, the invention relates to the provision of such novel structuralcomponents which include hollow components adapted to accept concrete orother material therein to enable a structure erected therefrom to beanchored to a base and converted into a permanent and essentiallyindestructible structure which will withstand earthquakes, tornadoes andother natural phenomena. The invention also relates to the method ofproducing such components.

While the structural components of the invention can be used in theerection of a wide range of structures, it is of particular note thattheir existence now enables low cost durable or permanent housing to beprovided for the masses throughout the word regardless of the climaticconditions.

DESCRIPTION OF THE PRIOR ART

While the use of plastic to form wall panels or the like for use inbuilding construction has been proposed, such panels have not had thenecessary load bearing or other structural requirements to formpractical structures which could be mass produced at low cost andquickly easily assembled to erect durable low cost structures and, inparticular, low cost housing.

U.S. Pat. No. 3,992,839, for instance, discloses a plastic panelfabricated from separate panel members, preferably formed of polyvinylchloride which snap together to form a thin wall panel. The panels inturn are formed to snap together to provide a wall structure. Suchfabricated panels are inherently weak and lack the strength and loadbearing capacity to form adequate structural components for use forinstance in the forming of the walls and roof of a practical durablebuilding.

U.S. Pat. No. 3,662,507 discloses the use of tongue and groovedindividually prefabricated panels said to be preferably of plastic whichare bonded or glued together and used particularly for the forming ofbasement walls. Such panels do not permit of high speed production andare not capable of being quickly and easily interlocked together in theerection of a house or other structure.

U.S. Pat. No. 4,557,091 discloses a hollow panel member having a widthof about one and one-half inches (11/2") and a complicated interiorformed by pultrusion, a process involving drawing long glass strands anda plastic binding material forcefully through a die under heat to formthe glass strands into a compacted glass mat bound together by theplastic material. Such a process is prohibitively slow and expensive andthe panels themselves do not provide acceptable or practical structuresfor forming the walls and roofing of a housing system such ascontemplated by the present invention.

EP-A-O 320,745 discloses an arrangement of hollow interlockingstructural components for a modular building which it is said maycomprise extruded thermoplastic resin preferably reinforced withpreferably about 30 per cent by weight glass fibers such as described inU.S. Pat. No. 4,536,630. Such proposed components are,however,unsuitable for practical housing as they are rough, abrasive,brittle and are subject to fracture and weather deterioration.

Further, the presence of substantial concentrations of glass fibers inthe resin renders such components extremely difficult to extrude and thefibers are destructive of the extruding dies. If the glass fibers aretoo large or too concentrated, it is simply not practical to extrudethem at all.

According to GB 2,028,228A, there is described a method of coating apolycarbonate sheet with an adherent synthetic resin ultra violetprotective layer. In this method, an extruded resin layer, particularlymethyl methacrylate and/or methyl acrylate is brought into contact witha surface of a planar extruded polycarbonate sheet while both are atelevated extrusion temperatures. The layers are then preferablycalendered no effect adhestion therebetween.

The acrylic glass layer of GB 2,029,228A is non an impact or scratchresisting layer and simply protects against ultraviolet radiation. Also,it is a specific requirement of GB 2,028,228A that the protectiveacrylic glass layer be extremely thin being limited to 100 microns andpreferably 50 micros as otherwise transmission of cracks into thepolycarbonate layer may occur. To provide scratch protection, theacrylic glass layer in turn is coated with a scratch resistant coatingby means of a coating solution.

The cost of attempting to produce the hollow interlocking structuralcomponents of the present invention using polycarbonate material as asubstrate and acrylic glass as a coating would be prohibitive and itwould not be possible to calendar any hollow co-extrusion withoutcollapsing same. Moreover, the acrylic glass layer would not provide theprotection against impact or scratching and the like and wouldnecessitate a further protective coating.

SUMMARY OF THE INVENTION

The present invention resides in one of its aspects in the providing ofnovel thermoplastic structural components which can be quickly andeasily interconnected to erect a wide range of structures from simplewalls, fences, and enclosures, to complete houses or buildings, saidthermoplastic structural components incorporating a reinforcingconstituent imparting structural strength and expansion control theretoand flowable with the thermoplastic material through an extrusion die,said components being extruded into an integral essentially rigidstructural shape having the reinforcing constituent distributedthroughout the thermoplastic material, said structural components beingconfigured to present means for interconnection with adjoiningstructural components so that they can be easily and quickly lockedtogether in the erection of the structure desired.

The structural components according to the invention include extrudedhollow panels, extruded hollow panel box connectors or columns, extrudedhollow beams and adapters, and extruded panel connectors, all of whichare provided with integrally formed means to enable interlockingconnection with adjoining structural components for quick and easyassembly into the structure being erected.

Also according to the invention, the hollow wall panels and columns havea structural strength to accept the pouring of concrete or the liketherein without deformation to provide permanent essentiallyindestructible wall structures.

In the case of the erection of a house or building, it will beunderstood that with the walls of the house or building erected on aconcrete pad with the wall panels and/or wall panel connecting columnsof the invention anchored with concrete to the pad a permanent roofsupporting wall structure resistant to tornadoes, earthquakes and othernatural phenomena is provided.

According to the invention, there is provided hollow rectilinearextruded thermoplastic structural components for a structural system inwhich said components have spaced longitudinally extending interlockingmeans for slidable interlocking engagement with adjacent matingcomponents characterized in that each said hollow component is aco-extrusion of a hollow substrate and an impact resistant and weatherprotecting skin substantially thinner than the walls of said substrate,said substrate comprises a polyvinyl chloride reinforced with areinforcing and expansion controlling constituent extruded into a hollowform having a rough surface with said co-extruded impact resistant andweather protecting skin (47) covering the surfaces of said hollowcomponent which are exposed as exterior walls where said hollowcomponent is interlocked with a mating component, said skin has athickness sufficient to cover and seal and interlock with the underlyingrough substrate surface to present said exposed exterior walls as planarsmooth surfaces. In a highly practical embodiment of the invention theprotective skin has a thickness at least of the order of about 0.015inches, and the substrate has a thickness of the order of about 4 to 5times the thickness of the skin.

In its preferred form, the invention resides in forming the structuralthermoplastic components aforesaid by extruding such components to havea polyvinyl core or substrate having reinforcing glass fibers anchoredin and distributed therethroughout imparting tensile strength andexpansion control thereto while co-extruding the smooth thermoplasticskin on the exposed exterior surfaces of said core, the said skinembedding and interlocking with glass fiber portions that are exposed atthe interface between said reinforced core and said skin.

In accordance with the preferred form of the invention, thethermoplastic skin provides an attractive maintenance free smoothsurface adding to the appearance and ease of handling and interlockingthe structural components as well as providing an impact resistantsurface protecting the glass fiber reinforced core and the embeddedglass fibers against external shock. Moreover, the thermoplastic skincan be colored as desired and provided with appropriate ultra violetprotective agents as will be understood to protect such color andprevent weathering.

The structural system of the invention has particular value in thehousing field whereby a house or building may be constructed on aconcrete pad and formed of interconnected extruded structural componentsas aforesaid including hollow wall and roof panels and connectingcolumns. The wall panels are anchored to the concrete pad by concreteintroduced internally into said hollow wall panels and/or connectingcolumns as desired. It will also be understood that if desired the housestructure, including the walls and roof, can be clad with any decorativeexterior as desired.

The invention further resides in the method forming the structuralcomponents by coextruding the smooth thermoplastic skin and thereinforced polyvinyl substrate to facilitate extrusion and to effect thebonding therebetween.

These and other features of :he invention will be understood fromfollowing detailed description taken in conjunction with theaccompanying drawings

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a house constructed of extrudedthermoplastic structural components in accordance with the invention.

FIG. 2 is a broken away view showing how the wall panels of the housesit on a concrete pad.

FIG. 3 is an enlarged perspective broken away view illustrating theseating of a wall panel on the concrete pad with the arrow indicatingwhere anchoring and reinforcing concrete or the like can be introduced.

FIG. 4 is an enlarged broken away perspective view illustrating a pairof panel members and a joiner therefor ready to be assembled.

FIG. 5 is an enlarged end view illustrating the manner in which thejoiner connects to adjacent panel components.

FIG. 6 is a broken away cross-sectional view illustrating the structureof a typical extruded structural component having a thermal plastic coreor substrate incorporating reinforcing glass fibers with the exposedexterior surface covered with a smooth thermoplastic skin sealing thesubstrate surface and embedding the glass fibers to be anchored therebyto the substrate.

FIG. 7 is a cross-sectional view on line 7--7 of FIG. 6.

FIG. 8 is a broken away perspective view illustrating the assemblage ofthe exterior wall panels and interior wall panel and the roof panels atthe ridge of the house.

FIG. 9 is a broken away perspective view illustrating a wall joining boxconnector or column provided with interlocking means to receive achannel forming insert to carry electrical wiring internally of thewall.

FIGS. 10 and 11 illustrate other forms of panel box connectors orcolumns.

FIG. 12 is a broken away perspective view illustrating the mounting ofthe lower end of a roof panel on the wall structure and the capping forsuch lower end roof panel.

FIG. 13 is a broken away perspective view of a wall corner illustratinghow the hollow wall panels and corner box connector or column constituteconcrete forms to receive concrete or the like to anchor the wallstructure to the concrete pad and to create an impregnable rigid wallstructure of discrete concrete filled cells capable of withstandingearthquakes, tornadoes and other natural phenomena while at the sametime providing effective insulation against heat and cold transfer.

FIG. 14 is a cross-sectional view illustrating a window installationusing an adapter configured to interlock with the wall columns andsupporting a standard window.

FIG. 15 is a top plan view of a wall which may be the wall of anystructure as well as that of a house embodying the invention andillustrating the use of concrete only in the box connectors or columns.

FIG. 16 is a broken away top plan view illustrating a wall structure inwhich the individual cells of the panels themselves as well as the boxconnector or column joiner are filled with concrete for maximum wallstrength.

FIG. 16a is a top view of a concrete pouring guide.

FIG. 16b is a top view of the concrete guide of FIG. 15a fitted atop awall panel used to provide the concrete filled wall structure of FIG.16.

FIG. 17 is broken away cross-sectional view illustrating one manner ofconnecting the roof panels to the house walls.

FIG. 18 is an enlarged broken away end view of a portion of a practicalexample of panel component or member embodying the invention andillustrating the relative thicknesses of the outer walls of thereinforced core and the internal connecting webs or walls and the bondedskin layer sealing the exposed external walls of the panel.

FIG. 19 is a broken away view illustrating an extruded reinforced wallpanel embodying the invention having a decorative cladding applied tothe exterior surface.

FIG. 20 is a view of a non load bearing interior wall panel in which theskin has been replaced by a coating such as paint.

FIG. 21 is an elevational view of a fence, wall, sound barrier or othersimilar structure embodying the invention and erected with structuralpanels and connectors of the invention.

FIG. 22 is a diagram illustrating an enclosure erected according to theinvention with structural panels and connectors of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The structural components of the invention have great utility in theerection of a wide range of structures but have special importance inthe field of housing since there is a desperate need for low costdurable or permanent housing throughout the world which efforts to datehave not been able to resolve. The requirements of such housing are thatthey must be constructed from components that can be massed produced atlow cost and quickly and easily assembled to form a durable or permanentstructure by unskilled workman. Further the resulting structure must besuch as to withstand wide variations in climatic conditions and becapable of withstanding the shock of earthquakes, tornadoes, wind, hail,rain and snowstorms, high humidity, wide temperature ranges, withoutcorroding, rotting or rupturing. Such housing must also be impervious totermites and other insects. Additionally, to be truly and widelyaccepted, such housing must have a satisfactory aesthetic appeal.

The present invention in addition to its utility for erecting all kindsof other structures for the first time enables the provision of housingmeeting all of the above criteria as will hereinafter appear.

With reference to FIG. 1, a typical house which the invention provideshas walls 1 assembled from wall panels 2 and a roof 3 assembled fromroof panels 4 as shown in FIG. 8.

The wall and roof panels are configured to be connected into the housingstructure by interlocking mating engagement with adjoining members sothat they can be assembled without the use of tools as hereinafter morefully discussed.

As shown in FIG. 2, all that needs to be done to prepare the site of thehouse is to construct a concrete pad 5, having a reduced thicknessborder flange 6 forming a ledge to receive the wall panels 2, as shownparticularly in FIG. 3.

The wall panels 2 have spaced exterior and interior walls 7 and 8connected by transverse webs 9 forming internal cells 10 into whichconcrete can be poured as illustrated by the arrow A as desired toprovided an extremely strong permanent wall structure. Additionally, theconcrete pad can be provided with anchor rods 11 as desired projectingup into the cells 10 to anchor the concrete poured into the cells andhence the wall panels to the pad. A runner 12 is provided to containconcrete from seeping out underneath the wall panel.

As can be seen if FIG. 2 of the drawings, the walls of the house and thesize of the concrete pad are dimensioned such that there is a veryslight gap G to the inside of the walls at the thickened portion of thepad. This provides a tolerance to ensure that the walls will fit downaround the thick part of the pad and rest on the thinner border flange 6as again seen in FIG. 2 and as also shown in FIG. 3 of the drawings.

When the concrete is poured into the walls, it does, as found inconventional concrete pouring methods, contain a certain amount ofwater. As can again be seen in FIG. 3 of the drawings, the wall formingpanels are left open at their lower ends where they seat atop theconcrete pad flange 6. This allows the water in the concrete toeffectively drain out the bottom of the wall panels and, although runner12 does provide an effective guard against concrete seepage from beneaththe wall panels, it is not a water guard and therefore allows any waterfrom the concrete in the wall panels to drain off of the pad. The runner12 further provides a guide assisting in alignment of the wall panelsalong the outer edge of the concrete pad.

As illustrated in FIGS. 4 and 5, adjoining panels are adapted to beconnected by a joiner 13 and then, as shown in FIG. 15, the free end ofthe panels are interlocked with a vertical column 14. Column 14 is atypical column for interlocking with adjoining interlocked panel pairsintermediate the length of the wall while column 15 is a corner columnfor interlocking adjoining walls which meet at a corner. As shown inFIG. 15, the columns 14 and 15 are filled with concrete 16 and areanchored to the concrete pad by the anchor rods 11. FIG. 15 illustratesthe situation where only the connecting columns 14 and 15 receiveconcrete, whereas FIG. 16 illustrates concrete in both the column 14 andthe internal cells 10 of the wall panels 2.

If the house structure is intended to be subsequently moved, sand canemployed in place of concrete in the columns and/or internal wall panelcells as desired to give the structural strength and anchorage desired.Also, of course, the internal wall cells 10 and/or the locking wallcolumns 14 and 15 can be filled with material other than concreteincluding insulation material. Alternatively, the columns could befilled with concrete and the panels filled with insulation material orsuch other arrangements as desired.

To have the house of modular form, for convenience, the wall panels 2,joiner 13, and columns 14 and 15 have been dimensioned to provide alateral distance from center line of column to center line of column ofone meter. The thickness of the wall panels 2 from exterior wall 7 tointerior wall 8 has been conveniently selected as four inches as abalance between cost and structural strength. Such walls, of course, mayhave a greater thickness but this adds to the cost while substantiallythinner walls reduce wall strength and the amount of concrete that suchwalls can accept.

As illustrated in FIG. 12, the upper ends of the walls 1 are capped by ahollow wall cap beam 17 having flanges 18 embracing the exterior andinterior walls of the wall panel to firmly seat thereon. This wall capor beam is of a hollow configuration and has a sloping upper surface 19to support the lower ends of the roof panels 4.

As shown in FIG. 17, the means of securing the roof panels 4 to thesloping wall cap surface 19 may comprise a threaded rod 20 embedded inconcrete in one of a wall column 14 or internal wall panel cells 10 andprojecting up through wall cap 17 and a wedge clamp 21 secured by nut 22and washer 23 threaded onto the upper end of rod 20. Hollow end cap beam24 with flanges 25 embracing the upper and lower surfaces of the roofpanels closes off the lower ends of these panels but provide suitabledrainable openings 26 which also allow air circulation through thehollow roof panels 4.

As shown in FIG. 8, centrally of the depth of the house is a hollowridge panel or beam 27 of similar construction to the wall panels 2supported by a yolk 28 carried by a column 14. Interlocked on the top ofthe ridge beam 27 is a roof panel ridge connector beam 29 having slopingroof panel supporting surfaces 30 which terminate in upwardly andrearwardly extending flanges or fingers 31 which project into the cells32 of the roof panels 4 to overlie and hold the lower surfaces 33 ofsuch cells, thereby anchoring the upper ends of the roof panels to theridge beam 27. A ridge vent 34 is provided to cover the spacing betweenthe upper ends of the roof panels 4 and interlock therewith whileallowing air to circulate through the ridge vent, the roof cells 27 andout the vent openings 26 in the end cap 24. The roof panel ridge beam 27is provided with closed hollow sections 35 underlying the supportsurfaces 30 to impart strength and rigidity thereto.

The roof panels 4 may have dimensions similar to those of the wallpanels 2 but, where increased roof spans are required or heavy roofloads are anticipated, the depth of thickness of the roof panels that isthe separation between the lower roof surfaces 33 and the upper roofsurfaces 36 may be increased, for example to six inches and as well thegas well the glass fiber content may also be increased. Similarly, thedepth or thickness and glass content of the ridge panel beam can beincreased where heavy loading is to be expected.

In addition to the columns 14, for joining straight wall sections andthe corner columns 15, as illustrated in FIG. 11, columns 37 areprovided for connecting an internal wall panel 38 to the panels formingone of the external walls 1.

It is highly desirable to conceal the electrical wiring to be used inthe house internally within the walls. To this end, there is shown inFIG. 9 a column corresponding to column 14 and designated as 14' whichincludes a pair of spaced fingers 39 which project interiorly of thecolumn and are turned outwardly in opposite directions to provide slideguides for receiving a channel 40 having inturned flanges 41 whichslidingly interlock behind the fingers 39 to provide a separatecompartment 42 for receiving wiring 43 or other services.

This separate compartment 42 provided on assembly of the channel 40within the column 14' can be closed off upon concrete being poured intocolumn 14' to leave the channel open for the reception of the wiring 43.

FIGS. 16a and 16b show features which enable loading of the concreteinto the wall without exposing compartment 42 to the concrete. Inparticular, FIG. 16a shows a concrete guide or jig generally indicatedat 44 having a series of openings 45 provided therein. As shown in FIG.16b, the jig 44 is placed atop the wall structure and the openings inthe jig align generally centrally with each of the cells or compartments10 in the wall structure. Of particular interest, the opening throughthe jig over column 14' does not line up with the compartment 42 formedby the channel 40 engaged with the guides 39 which are protected by thebody of the jig. Channel 40 and guides 29 are in abutting contact withthe bottom of the jig and, therefore, when the concrete is pouredthrough the jig, the compartment 42 is effectively sealed off from theconcrete flow. The jig has the added benefit that it provides a toplevel to which the concrete is filled and, because of the smaller sizeof the openings in the jig relative to the compartment sizes, helps toprevent any overflow of concrete material from the wall structure.

It will be appreciated that to produce a stable, solid and permanentstructure such as, for example, a house structure as described aboverequires the various components panels such as the wall panels, wallconnecting columns and joiners, the roof panels, the wall beams such asthe wall caps and the ridge beams to have the structural strength andload bearing capacity to perform their functions. At the same time, tobe practical these components have to be capable of being produced inlarge quantities at low costs.

While ordinary thermoplastics such as vinyl chloride, eg. polyvinylchloride (PVC), can be readily extruded to a desired shaped, theresulting product does not have sufficient strength to constitute a loadbearing structural member adequate for the building of a substantialload withstanding or permanent structure. Further such a member hasunacceptable dimensional changes with temperature. On the other hand,strengthening the plastic material in a manner which renders ituneconomical to produce product therefrom is equally unacceptable.

The structural components of the present invention are achieved by theuse of a thermoplastic material reinforced in such a manner that thereinforced thermoplastic provides the requisite strength and expansioncontrol yet is still flowable through an extrusion die. In this way thecomponent can be continuously extruded with the reinforcing constituentsdistributed throughout the thermoplastic material and with the walls ofthe component being continuous and integral at their juncture.

While there are known thermoplastic reinforcing agents such as mineralor other fibers and known expansion controlling agents such as calciumcarbonate, a reinforcing agent or constituent particularly useful forthe present invention, comprises small glass fibers. These glass fiberswhen anchored in a thermoplastic material such as vinyl chloride, eg. apolyvinyl chloride (PVC), provide the requisite reinforcing andexpansion controlling characteristics suitable in the various structuralcomponents of the invention.

A suitable material incorporating small glass fibers which can be usedin the production of the structural components of the invention isavailable under the trade-mark FIBERLOC from the B.F. Goodrich Companyof Akron, Ohio, such material being described in detail in B. F.Goodrich's U.S. Pat. No 4,536,360 wherein very fine short glass fibersare bound within a composition of vinyl chloride resin.

The presence of glass fibers in the PVC or other thermoplastic materialwhile providing tensile strength and expansion control to the materialcreates an extrusion problem and, if they are too large and tooconcentrated, it is not practical to extrude the material. Preferablysuch fibers should be of the order of a few microns in diameter and afew millimeters in length and in concentrations not greater than, andpreferably substantially less than, about thirty-five percent by weightbased upon the combined weight of glass fibers and vinyl chlorideresins.

Also, the presence of the glass fibers creates a brittleness which makesa structure produced solely from a glass fiber reinforced plasticsubject to potential fracture from impact. This potential increases withincreased concentration of glass fibers.

According to the preferred form of the invention, the problemsencountered with the use of the glass fibers as the reinforcingconstituent while utilizing their beneficial reinforcing qualities havebeen resolved by co-extruding with the glass reinforced thermoplastic asmooth thermoplastic skin covering the external exposed surfaces of thevarious structural components.

The smooth plastic skin may be PVC, rigid PVC, semi-rigid PVC, ABS,polycarbonate. Suitable thermoplastics are available from G.E. under thetrade-mark GELOY and NORYL.

Thus, according to the preferred form of the invention, the structuralcomponents having the characteristics desired, as shown particularly inthe enlarged views FIGS. 6 and 7, comprises a core or substrate 46comprising a glass fiber reinforced thermoplastic such as PVC and aco-extruded smooth outer skin 47 covering the exposed exterior surfacesof the structural component.

The skin 47 serves a number of useful purposes. Because of the presenceof the glass fibers 48 in the core or substrate 46, the substrate issomewhat brittle and its surfaces are rough and abrasive with portionsof the glass fibers projecting through the surface of the substraterendering the substrate somewhat porous and susceptible to the ingressof moisture which can adversely effect the bond between the glass fibersand the thermoplastic material.

The co-extrusion of the thermoplastic skin covers and seals the outerexposed surfaces of the structural component against the ingress ofmoisture thereby maintaining the integrity of the binding of the glassfibers to substrate plastic. Further, the outer skin 47 not only coversexposed glass fibers 48 but these exposed glass fibers become embeddedin the thermoplastic material so the exterior surface of the componentis totally smooth. The glass fibers in turn in becoming embedded in theouter skin lock the skin to the substrate so that the expansion andcontraction of the outer skin is fixed to the expansion and contractionof the substrate which is controlled or limited by the presence of theincorporated glass fibers which have a much smaller coefficient ofexpansion than the plastic.

Another important function of the outer skin 47 is that thethermoplastic material selected for the skin can be formulated, as willbe appreciated by those skilled in the art, to include agents providingimpact resistance. Thus the skin can provide an impact resistant orabsorbing covering encasing the exposed surfaces of the structuralcomponent, thereby rendering the structural component impact resistant.

The outer skin 47 can also incorporate any desired coloring and can bemade resistant to ultraviolet radiation so that it will not fade by theinclusion of a weathering agent as will be understood by those skilledin the art.

The combination of the coextruded substrate 46 and smooth skin 47 thusenables the provision of structural components which are essentiallymaintenance free, and impact resistant, and which will not corrode, rotor rust and which will be impervious to moisture, termites, and otherinsects.

As particularly illustrated in FIG. 5, the walls of the panels, whetherwall panels 2 or roof panels 4, make provision for interconnection intothe house structure by being extruded to provide opposing slide channelsor grooves 49 inwardly of the panel edge or side walls 50.

The spacing between the exterior and interior surface of the panels at51 and 52 extending from the grooves 49 to the panel edge or side walls50 is reduced to accommodate the thickness of the ends or flanges 53 ofthe joiner 13 illustrated in FIG. 5 or the projecting walls 54 of thevarious columns 14, 15 and 31 illustrated in FIGS. 9, 10 and 11. Withthis arrangement, the exposed surfaces of the panels are flush with theexposed surfaces of the joiners or columns to present smooth continuousexposed surfaces.

The joiners 13 have inturned flanges 55 adapted to slidingly engage andseat in the grooves 49 in the wall and roof panels to form an interlocktherewith. Similarly, the box connectors or columns 14, 15 and 37 haveinturned flanges 56 adapted to slidingly engage and seat in such grooves49 to effect quick and simple sliding interlocking assembly of thecomponents without the use of tools.

To facilitate this sliding interlock the end or side walls 50 of thepanels are slightly concaved as illustrated in FIG. 5. This maintainsthe panel end 50 out of contact with the web 58 of the joiner which onassembly becomes interior of the wall. This web 58 of the joiner is notcovered with the skin 47 and would therefore resist sliding against thepanel end. Also this arrangement avoids any interference with thesliding interlock if the tolerances of the panel walls 50 and the joinerweb 58 are exceeded. The joiners smooth skin 47 extends around the endsof the inturned flanges 55 so that they easily slide within the grooves49 at the panel ends.

As noted with the panel and joiner components assembled the unskinnedjoiner webs 58 are contained internally within and protected by the wallor roof structure. In the same vein, the transverse walls 59 of thecolumns or box connectors 14, 15, and 39 are unskinned and, whenassembled, are contained internally within and protected by the wallstructure.

While the outer smooth plastic skin 47 presents a very attractiveappearance which may be colored as desired, as shown in FIG. 19 adecorative facing illustrated at 60 may be applied to the panels such aswall panel 2. This decorative facing can take any desired form such assimulated brick, stone, clapboard and the like. It will also beappreciated that the roofing panels may also have a facing simulate rooftiling, shingles, and the like, the facing being attached by anysuitable means diagrammatically illustrated at 61 in FIG. 20.

Where the wall panels are not required to have the same load bearingcapacity as the wall panels previously described in the preferredembodiment for the outside walls of the house, that is for instancewhere the walls are to form interior walls, the thermoplastic materialof these panels, such as the panel 62 in FIG. 20, may containreinforcing agents other than glass fibers. Such other reinforcingagents indicated at 63 may comprise other fibers such as mineral fibersor non fibrous material such as calcium carbonate which would be readilyflowable through an extrusion die. Further, the plastic outer skin maybe omitted.

In such cases, the exposed surfaces Of the panels can be decorated andcovered or sealed by a layer of paint 64 as illustrated in FIG. 20 or bywallpaper or decorative panelling and the like. paint 64 as illustratedin FIG. 20 or by wallpaper or decorative panelling and the like.

The method of forming the structural load bearing components comprisingthe panels 2 and 4, the columns 14, 15 and 31, the joiners 13 and thewall caps or beams and the roof panel end caps, according to theinvention involves coextruding the smooth thermoplastic material skinlayer 47 simultaneously with the glass fiber reinforced substratematerial 46 and utilizing such skin layer as a lubricant to facilitatethe flow of the substrate material through the forming dies. By socoextruding the skin layer protects the surfaces of the forming diescontacted thereby, isolating same from the abrasion of the exposed fiberglass ends or portions of the substrate material.

In the structural components such as the panels 2 and 4 which haveinternal transverse webs such as webs 9 bridging between the wallforming portions, extrusion is facilitated by having the width orthickness of these webs somewhat less than the thickness of the wallportions 7 and 8. As a practical example, with the thickness of the webs9 chosen at 0.065 inches, the wall portions may have a thickness of0.080 inches while the thickness of the skin 47 may be of the order of0.015 inches, thus making the panel walls 7 and 8 0.030 inches thickerthan the internal webs.

Structurally, the walls 8 and 9 of the panels can be looked at as theflanges of an I beam and the transverse webs 9 as the webs of the beamin considering loading capacity. Similarly, the ends of the joiners 13can be looked at as the flanges of an I beam while the transverse web orwall 58 is the web of the beam. The columns 14, 15 and 37 can beconsidered as box beams for structural purposes.

It will be appreciated that the example given is purely an example andthe specific dimensions and proportions can readily be altered asappreciated by those skilled in the art.

The individual structural components of the invention are extruded inlong continuous lengths and are cut off at the desired lengths required.In this connection, it will be appreciated that these components arecapable of being sawn and notched without rupture to provided for doorand window openings and the like to receive the windows 65 and doors 66illustrated in FIG. 1.

As shown in FIG. 14 for example, the window 65 may be a conventionalwindow having a standard plastic window frame 67 mounting the windowsash 68 carrying the glass 69. To mount the window, extruded hollowthermoplastic adapters 70 are provided which are formed with channels orgrooves 71 which interlock, for example, with the inturned flanges 56 ofone of the box columns, depending upon the position of the window,corner box column 15 being shown. The adaptors are proportioned so thatwith a window they span between two columns to maintain the chosen onemeter modular format of the house. Thus, the window unit with adaptors70 illustrated in FIG. 14 it will extend between interlock with thecorner column 15 and an intermediate column 15.

The adapter 70 is provided with legs 72 which interengage with and carrythe window frame 67. It will be understood that the window unitincluding the adapters 70 can be simply slid into position or assembledin the same manner as the panels and connectors are assembled withoutrequiring tools or other fastening means.

Similar arrangements can be provided for accommodating the doors 66which also are readily available in plastic as will be readilyappreciated.

While the use of the structural components of the invention to form ahouse or building is described in detail FIG. 21 shows the use ofstructural components according to the invention for producing a simplewall 73 such as a highway sound barrier, a fence or a divider. In thisconnection panels corresponding to panels 2 are provided and interlockedwith joiners 13 or if desired box connectors and anchored by concretepoured therein to a concrete base 74 with anchor rods 75. Such a wallwill have exceptional permanency, strength, and weatherability with lowcost materials and can be erected quickly and easily by simply slidingthe components into interlocking engagement. FIG. 22 shows indiagramatic form the use of panels 2, formed into a simple enclosure 76using corner box connectors or column 15

It will be understood from the foregoing that the invention providesstructural components and a structural system for erecting structuresfrom simple structures to complete buildings in which the structuralcomponents having the requisite load bearing and structural requirementscan be mass produced at low cost and can be erected and locked togetherby simply sliding them into place so that erection can be effectedrapidly and easily just by a pair of workmen.

In addition to their other advantages discussed above, the structuralcomponents have low heat retention, that is they form poor thermal sinksand do not readily transfer heat and cold. Thus, in using the structurefor building enclosures the wall structures of the enclosure,particularly when filled with concrete, provide excellent insulationagainst the transfer of heat and cold.

Again, for the building of housing or other buildings, the fact that theroof panels are hollow and provide air circulation as well as having lowthermal conductivity enables these panels to form excellent insulationagainst the transfer of heat and cold through to the interior of thebuilding.

It should also be noted that the interlocking connections between thevarious structural components provides a tortuous path effectivelyblocking the ingress of moisture at these points of connection while, ofcourse, the components themselves are impervious to moisturepenetration.

Although various preferred embodiments of the present invention havebeen described herein in detail, it will be appreciated by those skilledin the art, that variations may be made thereto without departing fromthe spirit of the invention or the scope of the appended claims.

I claim:
 1. Hollow rectilinear thermoplastic structural components for astructural building system in which said components have spacedlongitudinally extending interlocking means for slidable interlockingengagement with adjacent mating components characterized in that eachsaid hollow component is a co-extrusion of a hollow substrate and animpact resistant and weather protecting skin substantially thinner thanthe walls of said substrate, said substrate comprises a polyvinylchloride reinforced with a reinforcing and expansion controllingconstituent extruded into a hollow form having a rough surface with saidco-extruded impact resistant and weather protecting skin covering thesurfaces of said hollow component which are exposed as exterior wallswhen said hollow component is interlocked with a mating component, saidskin has a thickness sufficient to cover and seal and interlock with theunderlying rough substrate surfaces to present said exposed exteriorwalls as planar smooth surfaces.
 2. A hollow component according toclaim 1 characterized in that said skin has a thickness at least of theorder of about 0.015 inches and said substrate has a thickness of theorder of about 4 to 5 times the thickness of said protective skin.
 3. Ahollow component according to claims 1 or 2 characterized in that thespacing between opposing walls of said hollow component is of the orderof about 4 inches.
 4. A hollow component as claimed in claim 1characterized in that said polyvinyl chloride substrate reinforcingconstituent is selected from one or more of calcium carbonate and fineshort fibers.
 5. A hollow component according to claim 4 characterizedin that said fine short fibers are mineral fibers or glass fibersprojecting ends of which are embedded in said skin.
 6. A hollowcomponent as claimed in claims 4 or 5 in which said substrate surface isporous and said co-extruded skin seals the underlying substrate surfacesagainst the ingress of moisture.
 7. A hollow component according toclaim 1 characterized in that said polyvinyl chloride substratereinforcing agent comprises short glass fibers having a diameter of afew microns, the concentration of said glass fibers being a smallpercentage of the combined weight of glass fibers and polyvinylchloride.
 8. A component according to as claimed in claim 1characterized in that said skin comprises a polyvinyl chloridecontaining impact resisting and weathering agents.
 9. A component asclaimed in claim 1 characterized in that said hollow component comprisesa hollow panel having spaced sidewalls connected by edge walls andhaving internal web walls spanning between said sidewalls, saidsidewalls being formed with longitudinally extending inwardly projectingoppositely registering grooves adjacent each edge wall said groovesforming said interlocking means and said impact resisting and weatherprotecting skin totally encompasses the exterior surfaces of said panel.10. A panel according to claim 9 characterized in that said internalwebs are of a substrate material and are thinner than the substrateportion of said skin coated walls.
 11. A panel according to claims 9 or10 characterized in that the substrate portion of said skin coated wallshas a thickness of the order of 0.08 inches and said webs have athickness of the order of 0.065 inches.
 12. A panel according to claims9 or 10 characterized in that the skin coated edge walls are concaved.13. A structural component as claimed in claim 1 characterized in thatsaid component comprises a hollow box connector having walls providedwith opposed projecting flanges provided at their ends with oppositelyregistering inturned locking fingers said walls, flanges and inturnedfingers being coated with said protective skin.
 14. A hollow rectilinearthermoplastic structural component having spaced longitudinallyinterlocking means for slidably interlocking engagement with adjacentmating components characterized in that said component is a coextrusionof a hollow substrate comprised of polyvinyl chloride containing areinforcing and expansion controlling agent and a protectivethermoplastic skin covering surfaces of said hollow substrate which areexposed as external walls of said component when same is interlockedwith mating components, the walls of said substrate covered by said skinbeing substantially thicker than said protective skin and the width ofsaid component between said exterior walls being of the order of severaltens of times the combined thickness of said substrate and skin of saidskin covered substrate walls.
 15. A hollow rectilinear thermoplasticstructural component as claimed in claim 14 characterized in that it isextruded as a panel provided with locking grooves (49) and having aplurality of internal compartments defined by webs of substrate materialbridging between said skin covered substrate walls, said webs having athickness less than said skin covered substrate walls and substantiallygreater than the thickness of saw skin.
 16. A hollow rectilinearthermoplastic structural component as claimed in claim 14 characterizedin that it is extruded as a box connector having integral lockingfingers.
 17. A hollow rectilinear thermoplastic structural component asclaimed in claims 14, 15 or 16 characterized in that the thickness ofsaid skin covered substrate is at least of the order of about 08 inches,said skin is at least of the order of about 0.015 inches.
 18. A hollowrectilinear thermoplastic structural component as claimed in claims 14,15 and 16 in which said reinforcing and expansion controlling agent iscalcium carbonate.
 19. A hollow rectilinear thermoplastic structuralcomponent as claimed in claim 14 in which the width between saidexterior walls is of the order of about 4 inches.